Aetiological evaluation of hyponatremia in hospitalised patients and its prognostic implication in disease outcome

Satish Kumar Samal, Samir Sahu, Jaya Bhanu Kanwar, Subhashree Ray

Abstract

Background: Hyponatremia is very common in clinical practice. Proper evaluation of hyponatremia is essential as causes are many and management of it depends on the aetiology and its long-term outcome. Aetiological evaluation of hyponatremia in hospitalised patients and its prognostic implication in disease outcome was undertaken as such studies were rare in this zone.

Methods: One hundred patients whose serum sodium level was <135 mEq/L were studied. The serum sodium and osmolality and urinary sodium and osmolality were estimated in all. The degree of hyponatremia, outcome after treatment and duration of hospital stay were analysed.

Results: The mean age was 60.5 years. There were 73% males and 27% females. The incidence of hyponatremia was 10.7%. The mean serum sodium was 129.96 mEq/L and urinary sodium was 40.3 mEq/lL while the mean serum osmolality was 272.8 mOsm/kg and urinary osmolality was 357.7 mOsm/kg. Euvolemia, hypervolemia and hypovolemia were observed in 51%, 28% and 21% respectively. The common clinical features were drowsiness (22%), disorientation (20%), fever (28%), nausea (24%), anorexia (15%), vomiting (14%), hiccup (10%). The common causes were SIADH (34%), renal causes (15%), sepsis (13%), endocrinopathy (11%) and diuretics (11%). The common comorbidities were hypertension (66%) and diabetes mellitus (41%). The mortality was 7%. No side effect was observed during management of hyponatremia.

Conclusions: Proper management of hyponatremia irrespective of aetiology had a better prognosis. Factors which are modifiable should be searched and rectified.